Automatic gear shifting



11 sheets-Sheet 1 yJuly 19, 1938. A. A. HoDGKlNs u AUTOMATIC GEAR SHIF-TING Filed June 17, 1952 ATroRNE July 19, 1938'. u 'A. A. HoDGKlNs AUTOMATIC GEAR SHIFTING Filed June 1'7, 1932 1l Sheets-Sher, 2

INVENTR ALBERT A. HODGKINS July 19, 1938. A. A. HoD'GKlNs AUTOMATIC GEAR SHIFTING Filed June 17, 1932 1l Sheets-Sheet I5 INVENTOR zTALHoDGKINs July 19, 192.8. A, A, HODGKINS 2,124,507

AUTOMATIC GEAR SHIFTING t Filed June 17", 1952 11 sheets-sheet 4 INVENTOR ALBERTA. HODGKINS BY July 19, 1938.

A. A. HODGKINS AUTOMATIC GEAR SHIFTING Filed June 17, 1952 ll Sheets-Sheet 5 k di INVENTOR ATTORNE July 19, 1938.

A. A. HODGKINS AUTOMATIC GEAR SHIFTIG Filed June 1'7, 1932 1l Sheets-Sheet 6 INVENTOR ALBERTAHODGKINS BY' July 19, 1938i 'A A. HoDGKlNs AUTOMATIC GEAR SHIFTING l1 Sheets-Sheet 8 Filed` June 17, 1932 Ill lll..

Huma- A ALBERTAHODGKINS- f BY I ATTORNEY July 19, 3.938. A. A. HoDGKlNs AUTOMATIC GEAR SHIFTING 11 Sheets-Sheet 9 Filed June 17, 1932 wil 1i ilu". xflllmzm" om s Q. m #t lNvENToR ALBERT A.-HODGKI NS ATTORNEY /v mw mm f mm,

July 19, 1938'. 4 A. A. HoDGKlNs AUTOMATIC GEAR SHIFTINQ Fil'ed June 17, 1952 1.1 .Sheets-Sh/e-et 10 INVENTOR ALBERTAHDGKINS .BYCg

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' INVENToR LBERT A. HODGKlNS M 'EY Patented July 19, 1938l PATENT OFFICE j AUTOMATIC GEAR SBIFTING Albert A. Hodgkins, Leonia, N. J., assignor to Almarc, Inc., 'New `York, N. Y., a corporation of New York K Application June 17, 1932, serial Nac-11,714

' 4s claims. (C1. 19a-.01)

This invention relates broadly to the automatic performance of shifting movements, for

instance, in motor vehicles and more particularly to' the automatic control of the clutch and,

transmission gearing therefor,.although not so limited. Y

It has heretofore been proposed to cause the engagement and release of the clutch in a selfpropelled vehicle by linking the clutch actuating devices to the piston or diaphragm of a pneumatically operated motor actuated by the subatmospheric pressure inthe intake manifold of an internal combustion engine. To control the operation of the pneumatically operated motor, a valve has been provided in the communicating passage between the intake manifold and the pneumatic motor, which valve has been actuated mechanically from the throttle of the engine. In a copending lapplication by the present applicant, such valve controlling the said passage has been automatically operated by so devising vit that it is respmsive to variations in the uid pressure. It has also been proposed, heretofore,

to provide automatic gear selecting in the change speed gearing of motor vehicles and the like in which fluid pressure, usually sub-atmospheric pressure on one side of the piston or vdiaphragm of a pneumatic motor and atmospheric pressure on the other side is utilized to actuate the gear shifting slip rods, which sub-atmospheric fluid pressure has also been made available by a connection with the intake manifold.

One object of the present invention is to provide an automatic gear shift which is controlled by variations in the motor load.

Another object of the invention is to provide means operative by variations in pressure dierential to control an automatic gear shift.

It is also an object of the present invention to provide instrumentalities whereby a motor, say, operated by fluid pressure differential can'be rendered inoperative when it is not desired that the motor effect a shifting movement.

The invention also seekspneumatically operated power means effecting the release of the drive shaft of change speed gearing from a source of power and the automatic release' of the gear shifting slip rods or shifter rods whereby pneumatic' or other devicesmay shift the gears, all in a construction in which the performance of the successive steps are automatic ,and dependent upon the completion of the performance of the preceding step.

It is also an object of the invention to obtain free wheeling of a self-propelled vehicle automatically whenever the momentum of the vehicle exceeds the speed of the prime mover and in which the instrumentality by which the free wheeling is obtained controls the shifting of the gears but which will not result in the accidental release of the gears or accidental alteration in the gear ratio.

Still another object of the invention is the provision of power cylinders operatively connected with the shift rods of a transmission in a compact construction wherein the power cylinders are enabled to conform to the mechanical movements necessary to effect the shifting movements.

Yet another object of the invention is the provision of power storing devices in association with the shift rods to returnthe shift rods to neutral position thereby assuring exact registration of the locking devices therefor. p

Another object of the invention is an improved selector valve and control therefor whereby a predetermined gear ratio may be selected.

The invention also seeks to prevent, in a pneumatically operated gear shift, the inadvertent disengagement of the gears due to a sudden and unexpected fluctuation. in the sub-atmospheric pressure in the intake manifold. To this end, the selector valveis provided with a check valve controlling communication between the source of iluid pressure variations and the valve.

Still another object of the invention is improvements in the construction of the power cylinders.

Another object of the invention is improvements in the control devices by which the clutch actuating devices controlthemovement of the shifter rods.

The invention also seeks to insure exact registration of the selector valve by the provision of indexing means thereon.

The invention also has for an object an automatic gear shifting means wherein the shifter rods and actuating devices thereof are enclosed within a leak proof transmission cover plate.

Yet another object of the invention is a transmission in which the pneumatic motors are carried on the sides of the transmission casing.

The invention also seeks an automatic shifting mechanism particularly adapted for motor vehicles which is practical from the standpoint of ease and convenience in manufacture, instal- 'lation and use.

'Ihese and other objects of the invention and the means for their attainment will be more ap- -parent from the following detailed description taken in connection with the accompanying drawings, illustrating one embodiment by which the invention'may be realized and in which:-

Figure 1 is a view showing the front end of a motor vehicle with an internal combustion engine, change speed gearing and clutch to which the invention is applied;

Figure 2 is a view on an enlarged scale showing the transmission mechanism in side elevation and power cylinders, partly in section, to effect the selective engagement ofthe transmission gearing under the control of the clutch shifting mech-.

anism; l

' Figure 3 is a view in front elevation showing the interconnecting controlling mechanism between the transmission and clutch actuating devices and looking from the left in Figure 2, and in the plane 'indicated substantially by the line 3-3 of Figure 2; y

Figure 4 is a view showing the transmission and power cylinders in rear elevation, looking from the right in Figure 2, and taken fin the plane indicated by the line 4-4; l Figure 5 is a view showing'the power cylinders and transmission in plan, looking from above, parts being broken away in the interest of clearness; A

Figure 6 is a detail sectional View, taken in the plane indicated by the line 7, looking 'in the direction of the arrows and showing the drift lock adapted to lock the inoperative shifter rod in neutral position by the movement of a companion shifter rod to an operative position, the drift lock being shown in inoperative position in this view;

Figure 7 is a view, in longitudinal section, showing the transmission gearing and shifter rods in yneutral position, the shifter rods being locked against movement by the clutch controlled locking devices;

Figure 8 is a detail view, in transverse section,

' taken on the plane indicated by the lin 8-8 in Figure 7 and lookingin the direction of the arrows;

Figure 9 is a fragmentary view in plan, showing -the shifter rods in the position occupied when the low speed gearing is in mesh;

Figure 10 is a detail View, in transverse section, showing the position of the drift `lock when the lowspeed gearing of the transmission is in mesh and with the shifter rod in neutral position locked against movement, the view being taken in the plane indicated by the line Ill--Ili of Figure 9,

4looking in the direction of the arrows;

Figure 11 isv a view similar to Figure 9 but l showing the positionof the shifter rods when the intermediate gearing of the transmission is encaged; l

Figure 12 is a detail view in transverse section,-

shwing the manner in which the shifter rod in neutral position is locked by the drift lock in the position ofthe shifter rods shownin Figure 11 and taken in the plane indicated by the line I2-I2 of Figure 11;

Figure 13 is a view similar to Figures 9 and 11, but showing the position of the shifter rods when the high speed gearingof the transmission is in mesh;

Figure 14 is a transverse sectional view showing the shifter rods, in the position of Figure 13, with the-shifter rod in neutral pcrition, locked lg the drift lock and taken on the line I4-l4 of Figure 15 is a view showing the position of the 6-6 of Figures 5 and shifter rods when the reverse gearing of the transmission i's in mesh;

Figure 16 is a transverseA s/ectional view taken l in the plane indicated by the line lG--IB of Figure 15, looking in the direction of the arrows and showing the position of the drift lock with respect to the shifter rods, in the position shown in Figure 15;

Figure 17 is a transverse sectional View showing the shifter rods and gear shifting fork and the actuating device therefor, for the intermediate,

and high speed ratio gearing, taken in the plane indicated by the line l1-l'l of Figure 7, looking in the direction of the arrows;

Figure 18 is a transverse sectional View taken in the plane indicated by the broken line l8--I8 of Figure 7, showing the shifter'rods, gear shifting forkand actuating mechanism therefor for the reverse and low speed ratio gearing;

Figure 19 is a detail View of the shifter rods, clutch control lock therefor and drift lock in the position in which the clutch controlled lock has released the shifter rods for movement by the power cylinders, and taken in the plane indicated by the line I9-l9 of Figure 17, looking in the direction of the arrows;

Figure 20 is a transverse sectional View taken in the plane indicated by the line 20 of Figure 19,

looking in the direction of the arrows, and showing the shifter rods released by the clutch controlled lock for movement;

Figure 21 is a vview in side elevation showing the transmission and automatic clutch operating mechanism, the gear shifting pneumatic motors or' power cyl-.aders being removed in the interest of -clearness;

Figure 22 is a detail view in section, on an enlarged scale, showing the check valve for admitting atmospheric pressure to the clutch operating power cylinder;

Figure 23 is an enlarged detail View showing,

in section, the adjustable bleed port for the clutch operating power cylinder; i Figure 24 is a fragmentary view showing, in outside elevation, the automatic Valve which controls communication between the intake manifold and the clutch operating pneumatic motor or power cylinder together with the manual devices for locking said valve in'inoperative position;

Figure 25 is a view in longitudinal section, taken in the plane indicated by the line 25-25 of Figure 24, looking in the direction of the arrows and showing the controlling valve in clutch engaged position;

Figure 26 is a view in side elevation of the valve illustrated in Figure 24 and -showing particularly the adjustable bleed port for admitting Y air at atmospheric pressure to the clutch operating power cylinders;

Figure 27 is a plan view of the valve of Figure 24 looking from above;

Figure 28 is a transverse sectional view of the valve of Figures' 24 through27,taken in the planes indicated by the broken line 28-28 of Figure 26, looking in the direction-of the arrows.

In Figure 1there is illustrated somewhatdiagrammatically the forward end of a motor vehicle in which an internal combustion engine is indicated at l in front of the dash 2 driving through a clutch of some convenient kind within the housing 3, a drive shaft 4 (Figure 7) entering the transmission `housing 5 disposedas is usual, beneath the iioor 6 of thevehicle. vehicle is guided, as is usual, by the steering The,

CII

to a point beside the engine. A' clutch pedal 9 protrudes through the floor of the vehicle, as is usual.

'I'he structural details of thel illustrated embodiment cannot conveniently be described in the order in which the various component elements automatically take part in the performance of the shifting movements. The operation of this device will, therefore, rst be briefly described in the order of operations: Assuming the engine I running, the transmission gearing 5n out of mesh and the clutch 3 disengaged, the driver of the vehicle will select the desired gear ratio, say, low gear, by manuallymoving the selector handle I2 to position opening communicationby selector valve I3 from the intake manifold I4 of the engine I to one of the pneumatic motors or power 'cylinders I5 or I6, say the motor I5, the pistonrof which is connected to a rock shaft 65 journalled in the cover plate I8 of the transmission case, adapted to perform the shifting movement into low gear. As soon as the vacuum builds up to the desired degree in the intake manifold I4, a clutch controlling valve I9 conveniently carried on the front of the dash 2 and responsive to such degree of suction, opens communication between the intake manifold I4 and a, pneumatic motor or power cylinder 20, the -piston of which is connected with the clutch actuating shaft 2I to effect the clutch release. Just prior to the release of the clutch, and as a concomitant of the actuation of the instrumentalities effecting the release of 'the clutch, gear shifting shifter `or slip rods are unlocked or `released by a connection 22, 23 between the clutch actuating shaft 2I and a shifter rod locking bar rock shaft 24 for movement thereby permitting the gear tol be brought into mesh.

In the illustrated embodiment, the transmis` sion affords three speeds forward and reverse. The rearwardly disposed pneumatic motor or power cylinder I6 effects actuation of the gear shifting devices for intermediate and high gear and the forwardlyv disposed pneumatic motor I5 effects actuation of the gear shifting devices for reverse and low gear.

While the invention is not concerned with the type of change speed gearing adopted,` there is shown for purposes of illustration in Figure '7, a type of transmission in which the gearing for high and intermediate speeds is constantly in 4mesh. Thus the drive shaft 4 entering the transmission case 5 has `fixed thereon a pinion 21 constantly in mesh with the gear 28 xed on the countershaft 29. Also on the countershaft 29 is xed a gear 30 constantly in mesh with a gear 3| freely rotatable on the driven'sha'ft 32. The

gears 21 and 3| are formed with or otherwise provided with dental clutch members 33 and 34, respectively, as is usual, adaptedto cooperate, respectively, with the internal dental clutch member of a sleeve 35l slidable on a gear 36 corresponding to the dental clutch members and xed on the driven shaft'32. Thus when the sleeve 35 is moved to the left, as viewed in Figure '7, the sleeve 35 and Vclutch member 33 connect the driven shaft 32 directly to the drive 35, the drive being then effected through the meshing gears 21 and v28 and the meshing gears an andi-31 for drive in intermediate speed. mso on the countershaft 29 is fixed a pinion 31, which is adapted to be lengaged by/a gear 38 slidably mounted by the splines 39 on the driven shaft 32, and when the pinion 31 and gear 38 are in mesh, the drive is-eifected from drive shaft 4 through the meshing gears 21-and 28 and 31 and y the reduced end of a piston rod, and 56, journalled for sliding movement in a removable head 51 for the cylinder and is connected at its outer extremity with the appropriate shifter rod and gear shifting fork in the following manner: `The piston rod 56 of cylinder I6 is connected to the extremity of an armv 58 flxed on the end of a rock shaft 59, journalled in the removable cover plate I8' for the transmission casing 5. On the inner extremity of the rock shaft 59 (Figure 17) is fixed a downwardly depending arm 66 connected with provision for relative movement in any convenient fashion with a shifter fork 44 conveniently removably secured, as by the fork screws 6I to the shifter rod 46 so that movement -of the piston 53 toward the left, as viewed in Figure 2, will rock the arm 66 in a clockwise direction to cause the dental clutch 35, 33 to engage for direct drive in high speed, while movement of the piston 53 to the right, as viewed in Figure 2,. will rock the arm 60 in a counter-clockwise direction to thereby shift the dental clutch 35, 34 into engagement for drive through the intermediate gear ratio.

The high and intermediate speed sleeve 35 is reciprocated by a shifter .fork 44, the arms of which are engaged in a collar 45 in the sleeve 35. Fork 44 is secured to a shifter rodv 46 (Figure `5) slidable in a chamber or bearing 41 in the cover plate I8 for the transmission housing 5. IThe low and reverse'gear 38 is provided with a collar 48 which is engaged by the arms of a shifter fork 49 secured to a companion low speed and reverse shifter rod 50, also mounted in a chamber or bearing 5I in the cover plate I8. The shifter rod forks 44 and 49 and shifter rods 46 and 50 are actuated by pneumatic motors I5 and I6, the movable walls or pistons of which are movable by pressure differential.

Similarly, the piston rod 55 of low speed and reverse cylinder I5 extendsrearwardly through a suitable bearing in the head for pivotal connectionwith the end of an arm 64 fixed o n the end of a rock shaft 65, also journalled in a bearing in the cover plate-|8 of the transmission casing 5. On the inner end of the rock shaft 65 is fixed a downwardly depending arm 66 suitably secured, as by a connection permitting relative movement l therebetween, with a fork 49 secured as by screws 61 to the shifter rod 59, and adapted to shift the gears for drive 'in low speed and drive in reverse. Thus when the piston 52 is moved to the left, as viewed in Figure 2, the arm 64 and rock shaft 65 and operating arm 66 are moved in a clockwise direction to slide the gear 38 into mesh with the gear 31 to provide the low gear ratio and wheny the piston 52 is moved to the right, as viewed in that figure, the arms 64 and 66 on the rock shaft 62' are moved in a counter-clockwise direction to cause engagement ofthe gear 38 with thereverse gear pinion 40.

To accommodate the cylinders |5 and |,6 and sliding movements of the piston rods 55 and 56 to the .variations in position of the end` of the arms-58 and'64, the cylinders l5 and 6 are pivoted in any convenient fashion, shown as by the pivot pins 68 passing through corresponding ears and lug 69 connecting each cylinder end remote from the` end in which the piston rod is jour.

nailed to some convenient part of the transmission housing 5, preferably in the axis of thecylinders.

' Shifter rod neutralizing device The chambers 41 and 5| (Figure '1) for the` shifter rods 46 and 50 are open at their rearward ends and ahousing 13 or end closure is carried on the rear end of the cover plate within which the endsl of the shifter rods reciprocate. The shifter rods are each provided with a power storing device 14 shown in the form of coil springs encircling the protruding ends 15 of the respective shifter rods, which ends 15 may, if desired, be of reduced diameter. These power storing devices 14 serve to return the shifterl rods to neutral position when released from a position to which they have been moved in the selection of a gear ratio. By disposing the returning springs directly on the shifter rods as distinguished from associating them with the power cylinder, an exact reg-l 15 of the rod by a collar 18 fixed as in a groovel 19 therein. The annular stop11 is adapted to engage a shoulder 80 formed in the spring housing and the spring seat 16`is freely slidable on the reduced end 15 of the shifter rod but is engaged in the neutral position by a limiting stop formed on the bearing. The other end of this spring 14 is engaged by a seat 8| also sliding on the reduced rod end 15 and preferably xed against displacement -in one direction by contacting with the portion of increased diameter of the shifter rod operating in the'shifter rod chamber.y 'Ihe end wall of the shifter 10d chamber serves as an abutment 82 or limiting stop for the spring seat 8|. the power storing device 14 is provided with a stop 83 against which the end 15 of the shifter rod may abut in one extreme position ofvits movement. At the front end of the shifter, rod bearing,it is `provided with a limitingstop 84.

Thus when a. shifter rod 46 or 50 is moved to the right as viewed 4in Figures 5 and '1,H its end abuts against the end or abutment 83-in the end of the spring housing 13'. At the same time, the annular stop 11 and/or spring seat 16 is in engagement with the spring limit stop 00 and as the rod carries with it, in its movement to the right, the spring seat 8|, the spring. 14 is compressed, thus storing up power or energy which, when the shifter rod is released, will enable the spring 14 to returnthe shifter rod lto neutral position when the seat 8| on the shifter rod is in abutting relation with the abutment 82 on the cover plate and the spring 14 is expanded. Simi# In its outer extremity, the chamber 13 for groove adapted in one position of movement of the locklarly, where the shifter rod is moved to the left, its left end abuts against the forwardvend orstop 84 therein of the cover plate and the spring seat 16 is carried away from the limit stop, again compressingthe spring 14 and storing up energy to return the shifter rod to neutral position when it is released for movement.

Shifter 10d lock: y To x the shifter rodsin their several operative positions, a lock is provided which, in the present instance,` takes the form. of balls |09 and I|0, or analogous rolling lor reciprocating or movable locking members which are held for movement of reciprocation inrecesses or ways and 9|,

respectively.' opening into the respective shifter rod chambers 41 and 5I and a locking bar chamber92 (Figures '1, 8 and 19) Where the transmission'is adapted to three speeds forward and reverse, two shifter rods 46 and 50 are provided and each shifter rod is formed with four recessesor peripheral grooves.

Shifter vrod 46 adapted to be coupled with the gear shifting devicesfor second and highspeed gear'ratio is provided with a recess 95by which,

as after explained, the shifter rod 46 is locked in neutral position and a recess 96 whereby the shifter rod is locked in high speed position and a recess 91 by which it is locked in intermediate position. The shifter rod is also provided with a recess 98 by which it is vlocked by a drift lock in neutral'position by the movement of the companion sli'ifter rodl 50 awayfrom neutral position.

It is desirable that the shifter rods 46 and 50 be locked against movement and hence the gear shifting devices be locked against a change in gear ratio or a movement not contemplated or intended. This is accomplished by preventing the movement of lthe shifter rods except when the 'clutch is disengaged.

As shown, the cover plate I8 of the transmission 5 is formed with a locking bar chamber 92 in a plane above' the plane of the shifter rod chambers 41 and 5|. This chamber 92 is also g shown as substantially cylindrical for convenience the shifter. rods 46 and 50.

At its forward end, the upper portion of the cover plate is formed with a bearing 99 for a rock shaft. |00, having an arm 93 thereon which is clutch actuated through the connections 22, 23 (Figure 1). Within a recess or extension |0| (Figure 7) of the locking bar chamber, an arm |02 fixed on the rock shaft |00 rota fes in a direction parallel to the axis thereof. The lower end of the arm |02 is conveniently formed with a rounded end |03 disposed in a groove |04 in the endof the locking bar |05. Thus as the rock shaft v|00 is turned, the lockingbar |05 is moved from `one extreme position in which, say, the forward l ing bar (Figure 19) to register with the passages or ways 90 and 9| toreceive a pprtion of the locking members or balls |09 and ||0 protruding therein. In another position of he locking bar y covers the ways 90 and 9| and holds the balls |09 and |.I0 downwardly into one of the recesses 95, 96 and 91 or the corresponding recesses in the shifter rod 50.

responding to those of the shifter rod 46, a recess ||2 being the neutral recess, a recess H3 being the recess for locking in low gear position, a recess ||4 forA reverse drive position and a recess |,|5 for locking by the drift lock when this shifter rod 50 is in neutral position.

Shifter rod operation Referring now to Figure 5, the shifter rods 46 and 50 are shown in neutral position with the restoring springs 14 normally extended although suiciently compressed, and the spring seat stops 18 and 8| abutting the limit stops 80 and 82, respectively, of the spring chambers, because of the inherent resiliency and degree of compression of the springs, as shown. In this position, the grooves 95 and |2 are in register with the ways 90 and 9|, respectively (Figure 8). assumed, further, that the locking bar |05 occupies theposition shown in Figure 7, held through spring 236, wherein the detents |09 and ||0'are held in the grooves 95 and ||2 by the enlarged or locking portion of the locking bar |05. In this position of the locking bar, the clutch is engaged. Assuming now that it is desired to shift the gears from neutral to low or iirst speed, the clutch being disengaged. This causes the movement of the locking barA |05 until the peripheral groove |08 is in register with the ways 90 and 9|, as in Figure 19. Thus the groove |08 is so positioned as to receive the balls or detents |09 and s ||0 when the power cylinder or motor I5 moves the shifter rod 50 forwardly to the position shown in Figure 9, thereby compressing the restoring spring 14 thereon and bringing the groove I|3 in register With the Way 9|. Then when the clutch is reengaged and the locking bar |05 shifted to the rear by spring 230, the detents |09 and H0 are cammed downwardly by the curved side of the groove |08 into the neutral recess 95 of the bar 46 and into the low speed recess 3 of the shifter rod 50, thereby locking both these shifter rods in position and locking the gears in the low gear ratio.

To shift from low gear tointermediate gear,

' the clutch is again released to thereby again bring the recess |08 in the locking bar |05 in register with the ways 90 and 9|, thereby releasing the detents |09 and ||0 for movement, thereby permitting the return spring |4 to return the shifter rod 50 to neutral position shown in Figure 11. The shifter rod 46 is then moved to the position shown in Figure 11 by the piston of the .power cylinder I6 to bring the recess 91 in register with the way 90, whereafter the clutch is again reengaged, again moving the locking bar to the position shown in Figure 7, and again camming the detents |09 and I0 into-the respective grooves 91 and |2 and locking the shifter rods'inthat position. 'As observed in Figure 11, the return spring 14 on rod 46 is thus compressed against the limit stop in the return spring housing 13, thereby storing energy for effecting the return of the shifter rod 46 to neutral positionl when again unlocked by the clutch controlled locking bar 05 and when permitted by movement of the appropriate cylinder I6. To change the gear ratio The companion shifter rod 50l is similarly formed withrecesses in number cor-A It may beA from intermediate to high speed, the locking bar |05 is again moved to release the detents |09, ||0 and the piston of cylinder I6 moving to the left again shifts the shifter rod 46 in the opposite direction (i. e., to the left) to bring theY recess 96 in register with the way and to the position shown in Figure 13, where the shifter rods are again locked by the clutch controlled locking detents l09, 0 by movement of the locking bar |05. The reverse position for the shifter rods is.

It is desirable that further control of the shifter rods 46 and 50 be had in order that, while any one of the shifter rods may be freely moved when all are in a given or neutral position, nevertheless when one has been moved from that position, it

will be impossible to move the others until the first has been returned to its original position. This is effected, generally, in the illustrated embodiment by the provision of recesses 98 and H5 formed inthe respective ends of the shifter rods 46 and 50 within each of which is adapted to lie thelower zone of a ball ||1, ||8 (Figure 10) shifter rods releasably in neutral position.

Disposed in the cover plate I8 of the transmission housing 5, forwardly of the locking bar recess |0|, is a forwardly facing recess 9 of substantially cylindrical form as shown, for instance, in Figures 7, 19 and 10, from which recess a passage |20 leads to the shifter rod chamber 41 and another passage |2| leads to the shifter rod chamber 5|. 'I'hus when either of the shifter rods are shifted, one of the balls is cammed out of the groove and may move upwardly and inwardly so as to project a substantial distance within the drift lock recess I9.

In order, however, that one of the rods will be prevented from .being moved until the adjacent v which serve as detents to selectively hold the vrod is in neutral position, it is necessary to provide means to hold the corresponding ball within f the groove in one rod when the other is shifted. To accomplish this, there is mounted in the drift lock chamber ||9 a drift lock rocker |22 of substantially cylindrical or disc-like shape pivotally mounted for rotation, say, on a pivot pin |23 passing through the cover plate 24 for the recess ||9 and threaded into the rear wall |06 thereof. Obviously the pin or other pivots may be omitted as the rocker |22, fltting in the recess 9, will turn on its axis and function.' The pin |23, however, serves as securing means for the cover |24 as well. Below the pivot |23 orvaxis, the rocker |22 may be provided with a depending lug |25 formed conveniently by cutting sector shaped pieces vout of the rocker to form recesses |26, |21

therein. The lug I 25 or finger may, if desired,

tively hold that rod against movement.

As shown in the drawings, the segmental recesses |26, |21 are of a size sumcienty to receivev r50. These grooves 98, |,I are curvilinear in cross section to facilitate the entrance into and urge the balls out of the grooves and the relative dis-- position and size of the rocker I22,`-the balls II1, II8 and the associated parts is such that when the one shifter rod, say, 50, is moved, the ball II8 will be moved outwardly in the raceway I2I to engage the side of the lug |25 and swing the rocker |22 about its pivot or axis so asto move the lug |25 to a position wherein its end engages the other ball |I1 (Figure 16) sol as to hold the latter in the raceway |20 and in the groove 98 and positively prevent any movement of the shifter rod 46. Thus, if the shifter rod 46 is at this time subjected to pressure, tending to move it longitudinally, this will tend to cam the ball I I1 from the recess 98 in the shifter 50d. This tendency will be resisted by the rocker '|22 and the pressure upon the ball I I1 will eventually be transmitted to the rocker |22 to be borne entirely by the pivot |23 or chamber wall, as the case may be, so that no force will be acting to urge the other ball |I3 toward lthe shifter rod 50 and thereby bind this rod so as-to oppose its movement.

'I'he rocker |22 is cut out in its upper portion or otherwise formed with bifurcated arms |30 Aand |3I shown more particularly in Figure 6. A compression spring I 32 is'mounted between ngers |33 and |34 formed on'a at segment |35 inserted in a slot |36 in the top wall |31 of recess OII9. It will be observed that the ends of the bifurcated arms |30 and I3I of the rocker |22 will straddle the fingers |33 and |34 and upon the respective sides of these ngers will engage the ends of the spring |32 so as to compress this'spring when the rocker is moved to one side or the other by a ball moved thereagainst, as shown for example in Figure 10. When the rod 46, for example, has

been returned to neutral position and the b'all II1 is again seated in the depression 41, the spring |32 will insure the return of the rocker |22 to its inoperative position, as shown in'Flgure 6. It `will be apparent that the spring |32 is free i to be compressed from either end, so that the one spring will .effect the return ofthe rocker arm |25 to its central position regardless of the direction in which it is moved.. u

Referring now to Figures 5, 6 and 9 through 16 and assuming that the shifter rods 46 and 50 are in the neutral positionindicated in Figures 5 and 6, itwill be observed thatthe' respective returning springs 14 are in extended position with the abutments' 11' in engagement with the shoulders 30 and the seats 3| at the other end of the springs 14 in engagement with the corresponding shoulders 32 formed on the walls of the shifter rod guidev passages.' It will be observed that the bolt controlled locking balls |09, IIO are depressed by means of the bolt I05'into the neutral grooves 96and. I2. Whennow the proper end of the proper power cylinder, say, 4I6, is in communication with a source of reduced` air pressure, the pressure of atmospheric air on the opposite side of the piston 52 will tend to move the crank 64 and thereby rock the shaft 65 to move the fork 49 and with it the shifter rod 50 forwardly to the position shown in Figure 9 providing, of course, that the groove |03 of the clutch controlled locking bolt |05 (Figure 19) is in registerwith the raceway to permit the ball I I0 to move upwardly into the groove. This al:-o compresses the/return spring 14 from the forward end thereof so that the return spring 14 will tend to return the shifter rod 50 to initial position intermediate the ends of the passage. As the shifter rod moves forwardly, the clutch controlled"locking ball |I0 will be cammed out of the groove I|2 to permit the movement of the rod. Furthermore, as the rod moves forward the vdrift lock ball IIB will be cammed out of the depression |I5 and engaging against the lug |25, will swing the rocker |22 from the position shown in Figure 6 to the position shown in Figure 10, wherein the end of the lug |25 engages the other ball I|1 and locksthe rod 46 against movement.

If now the shift is to be made to intermediate gear, the operator must move the'rod 46 and the rod 50 must be returned to neutral position.

This, however, does not require any care on the part of the operator; he merely actuates the selector I2 to open the valve |3 to the proper cylinder I6 to reduce the air pressure therein on the rear face of the piston 53. At this time, the other end of this cylinder I6 and both ends of the other cylinder I5 will be vented to the atmosphere and the spring 14 will tend to move the rod 50 back to neutral position, as shown in Figure 11. Likewise, the reduced pressure existin'g in the rear end of the cylinderl I6 operating the rod 46 will cause its force to move the rod 46 rearwardly to the position shownl in Figure 11, where the ball |09 falls into the groove 91 while the other ball |I0 moves into the neutral groove II2 of rod l50' and the reengagement of the clutch effects the movement of the bolt |05 to locking position to hold the balls |09, I0 in the respective grooves 91 and ||2 in the shifter rods. This movement has resulted in the locking vof the ball |I8 in the groove II5 of shifterrod 50 by the drift lock lug |25 as shown in Figure 12, thus locking rod 50 against movement. Therefore at this time pressure has been exerted upon both of the shifter rods tending to move rod 50 to its yneutral position and the other to its locking position. Both of the rods will be locked against movement due 'to the locking'bolt |05. However, when this bolt is moved forwardly both rods will be released asfar as this part of the structure is concerned.

It is at this time that the rod controlling mechanism or drift lock |22, I |I3 is particularly advantageous.

, trolling mechanism but, as. shown in Figure 12,

the rod 50 will be held against movement by the lug |26 of the rocker |22 which engages the ball |I3 and holds it in the depression II5. The rod 46 is, however, free to move and will be moved by the return spring 14back to neutral position. In this position, the drift lock ball II1 will drop into the groove 98 and permit the drift lock compression spring |32 to move the rocker |22 from the position shown in Figure 12 to the neutral position shown in Figure 6 and wherein the ball |09 will be released andthe shift rod 46 will be moved by the piston I6 in the Vproper direction. Figures 10, 12,"14' and 16 show the various positions assumed by the drift lock in locking the inoperative shifter rod (i. e., that one in neutral position) at the different gear shiing positions. y

It will, therefore, be apparent'that one of the shifter rods will be retained against movement from neutral position until the other has been returned to neutral position, and it will also be observed that the rod 46say, will be retained in its neutral position without the action of any force which tends to oppose the return movement of the other rod,` say, 50, or bind this rod against movement,although at the. same time the locking of one of the rods is controlled by the other in that the one is released'when the other is returned to a neutral position.

Gear selecting Briefly, in the illustrated embodiment, a selector valve I3 is provided controlling communication between the intake manifold I4 and the cylinders 5, I6 on the respective sides of the pistons 52 and 53 and this selector valve I3 is preferably controlled from a. point convenient to the operator of the vehicle, say, on the-top of the steering column 8.

The steering column of a motor vehicle is indicated at I4I and the steering post has fixed thereon a steering wheel 1, the hub of which is indicated at |44. 'Ihe space within the steering column may be occupied by adjusting tubes for the spark and/or gas, not shown. Centrally thereof, is shown the selector 'shaft |45 by which the Valve I3 controlling the communication between the pneumatic motors or power cylinders I5, I6 and the source of vacuum I4 iscontrolled by the driver of the vehicle.

The selector shaft |45 -extends downwardly through the steering column and protrudes from the lower end thereof for connection with the,v valve member |69, of a multi-way selector valve I3 whereof the tubular valve casing is indicated at |10 suitably mounted, as by a bracket I1I on and is enlarged, as at |15, at the end remote from theselector shaft |45, and interiorly threaded to receive the coupling member |16 securing the end of a tube |11 leading to the intake manifold I4 of the internal combustion engine.

The other end of the'valve casing |10 proximate the selector shaft |45 is formed with series of bosses |81, which are individually apertured as the outlet ports leading to the power cylinders effecting the shifting of the gears. Thus, the reverse port communicates through tube |89 with the rear end of the cylinder I5, i. e., with that side of the piston 52 effecting the meshing of the gears for reverse drive and the low speed port is in communication through tube |9I with the front end of cylinder I5, i. e., to that side of the piston 52 effecting meshing of the gears for the low gear ratio. The port is in communication, through tube |93, with the rear end of cylinder I6, i. e., to that side of the other piston 53 effecting the meshing of the gears for inter.-

mediate speed and the high speed port |94 communicates, through tube |95, with the front end of cylinder I6, i. e., to that side of said piston movements.

Piston construction In the illustrated embodiment, Figure 2, the cylinder I5 or I 6 is cup-shaped, say, pressed from metal and is conveniently formed with an outwardly directed peripheral ange 2|4 as one of cooperating locking means with the piston head 51. The peripheryv of the piston head 51 overlies the flange 2|4 and has centering means in the form-of a flange 2|5 telescoping within the cup and a bearing 2| 6 for the piston rod 55 or 56. The cylinderA head 51 is peripherally threaded for engagement with the internal threads of an annulus 224 having an inturned ange 225 which, when the annulus is telescoped over the cylinder, engages the flange 2|5 and clamps the cylinder head'tightly on the cylinder.

It will be noted that both cylinders I5 and I6 contain therein pistons 52, 53, respectively. Each piston comprises generally a disc or piston proper 2|1 carried on the reduced end of the piston rod and formed with a peripheral groove 2AI8 for the reception of a ring-like piston spring 2I9, while outwardly on each face of the piston 2 I1 are cup leathers 220 whereof the peripheries 22| are lapped inwardly over the edgey of the piston and over the piston spring 2I9 to form a pneumatic sea-l; the leathers being held in position by metallic plates 222 on the outer faces of the leathers and the entire assembly being held in position on the reduced end of the piston rod by the shoulder 30 at the inner end thereof and a nut 223 on the outer end. Thus only one piston spring is required to urge the inwardly turned ends of the cup leathers into sealing engagement with the wall of the cylinder. 35

Interconnection between clutch and shifter rod' lock l In its preferred embodiment, the invention seeks the automatic control of. the gear shifting This is accomplished by retaining the shifter rods 46 and 50 against movement until the clutch is released, for instance, by interconnecting the clutch actuating devices 2| with the shifter rod locking bar |05 so that only when the clutch is'released either automatically, responsive to conditions in the intake manifold of the engine or otherwise, or manually at the will of the operator, can the shifter rods 46 and 50 be released for movement and the gear shifting movements effected.

There is fixed on the clutch actuatingshaft 2| an arm 22 (Figures 2, 3, 4 and 21) formed with an elongated slot 226 within which is received the pin 221 of a clevis 228 adjustably carried on they end of a link 23, the upper end of which is turned inwardly, as at 229 (Figure -3), and pivotally received within the end of the arm 93 mounted on the rock shaft |00 actuating the locking bar I05hereinbefore described (Figures 7 and -19). 60

The arm 93 is normally urged in a counterclockwise direction, as viewed in Figure 2, i. e., to the locking position of the locking bar |05, by means of a tension spring 230 conveniently connected to the end 229 of the link 23 and secured at its 65 other end to some convenient part of the transmission housing 5.

Figures 7 and 2l illustrate the relation of parts whenthe clutch 3 is engaged and the shifter rods 46 and 50 locked by the locking bar -|05 against 70 movement. Assuming now that it is desired to shift the gears, the clutch pedal 9 may be manually depressed thereby causing the clutch aetW/ recing shaft 2| to turn in a counter-clockwise tion. This same mneutfmybe effected re- 75 81 sponsive to a variation in sub-atmospheric' pressures in the intake manifold |4 of the engine by the pneumatic'motor 2|) causing the rotation of the arm 23|, fixed on the clutch actuating shaft 2 in a counter-clockwise direction thereby causing a similar turning of the clutch operating shaft 2|. This rotation of the shaftl v2| in a counter-clockwise direction carries with it the arm 22, but movement of this arm does not pick up and cause corresponding movement of the link 23 until the arm 22 has brought the lower end of the slot 226 into engagement with the pin 22T-of the clevis 228 thereby causing the upward movement of the arm 93 and the unlocking of the shifter rods during the last portion of the movement of the clutch releasing devices, i. e., until just before the arm 23| reaches the dotted line position shown in Figure 21. When the clutch is to be reengaged and .the clutch actuating shaft 2| turned in a clockwise direction, the movement of the arm 22 downwardly does not affect the link 23 because, so soon as the clutch actuating 'shaft 2| commences to move, the spring 230 draws the shifter rod locking bar lever 93 downwardly.- 'Ihe purpose of. this construction is to insure that the clutch is fully opened before the gear shifter rods are unlocked and the lgears permitted to be shifted, and hence the parts are so designed that theclutch actuating devices must move through substantially three-quarters of their movement Clutch. control y It has been found that the conditions of subatmospheric pressure or vacuum in an internal combustion engine fluctuate with the load on the engine. That is, when there is no load on the engine, the downward movement of the pistons on the intake stroke increases the rariflcation in the intake manifold and combustion chamber. Similarly, this rarification in the intake manifold and combustion chamber increases as the throttle valve controlling the carburetor is closed. Thus, for example, when the vehicle is stationary and the engine idling, the rarilcation of atmosphere, or, as it is said, the vacuum inthe manifold is high. I f the throttle is opened, due to the inrush into the intake manifold and combustion chamber of the explosive mixture, the rarification or vacuum drops momentarily and then gradually builds up again as the pistons reciprocate. Thus, when the vehicle commences to move, rst because of the opening of the throttle and then because of the load on the engine, there results a decrease in the 'rarilcation of the atmosphere or vacuum in the manifold, but as the vehicle gathers momentum, the load on the engine decreases and the vacuum increases in the manifold and explosion chambers. Advantage is taken of this fluctuation of the fluid pressure in the manifold and explosionchambers by providing a valve which is susceptiblethereto and which controls the furnishing of power to motor means, for instance, controls communication between a iiuid pressure actuated motor and a source of fluid pressure. In'other words, when applied to the intake manifold and/or combustion chambers of an internal combustion engine or any other chamber in which the fluid pressure fiuctuates, the valve is responsive to fluctuations in the vacuum and is self-opening', and closing dependent upon the degree of rarefaction in the chambers.

The mechanism by which the clutch shifting movements are effected is illustrated in Figures i,

and 21 through 28, as a power actuator or servo motor 20, in which differential pressures are obtained by means of rpartial vacuum on one side of a piston 235, and atmospheric air or other high pressure fluid on the other side, suction for producing the desired differential pressure being shown as obtained from the intake manifold |4 (Figure 1) of the internal combustion engine I and the motor 20 is shown as applied to the clutch shifting element 2|. The clutch shifting arm 23| is fixed on a shaft 2|. This arm 23| and the shaft 2| to which it is affixed normally assumes the position shown in full lines in Figure f is the foot pedal 9, which is normally retained in the elevated position by means of the spring 236.v The foot pedal 3 has a bearing surface 231 for engagement with the arm 23|. Thus, when the foot pedal 9 is depressed, the armv 23| is rotated in a counter-clockwise direction to release the clutch, but when the motor means 20, next to be described, is operated, the clutch operating shaft 2i is turned, but the foot pedal 9 does not move. To release the clutch automatically, the clutch arm 23| is connected to motor means preferably operated by fluid pressure differential, such as the movable wall or sliding piston 235 of a vacuum cylinder 2U. The piston 235 has secured thereto a piston rod 238 slidable ina bearing 239 in the removable cylinder head 240 of the cylinder 23, which piston rod 233 is connected to the end of the lever 23E by connecting means affording a lost motion connection therebetween. Such connecting means may be flexible and comprise a cable 24| passing over an idler pulley 242 for change of direction. Thus the cable 24| permits the foot pedal 9 to be depressed,vthus releasing the clutch without compelling the piston 235 to move within the cylinder 20, as will be understood.

The normal position of the piston 235 is in the forward end of the cylinder 20. By the port 243 (Figure 22), controlled by the spring pressed ball valve 244, the face of the piston 235 is subual return of the piston to initial position prevents too sudden engagement of the clutch elements, which would jolt and jar the mechanism. The interior of the cylinder 20 on the side of thepiston 235 remote from the bleed port 246, that is, on the face 241 of said piston, is subjected to the vacuum of the intake manifold through a port 248 connected by a flexible tube 249 to a pipe 25|) which, in turn, is connected by a valve structure I3, next to be described, to a vacuum feed tube 25| leading into the intake pipe or manifold |4 of the engine I. v

: Communication between tube sections 25| and 250, and hence between the motor 20, if pneumatically operated, and the suction inducing means I4, is controlled by a valve (Figure 25). I'his valve comprises a casing 254, having a bore or cylinder 255, preferably of constant diameter. 'I'he bore 255 is conveniently cylindrical, from manufacturing andoperating considerations, as

closed at'one end by a stop plate 258 formed con.-u

veniently, centrally, with a vent 251, wherebyv v the face 258 of the valve 259, exposed thereby.-

is subjected to the pressure of the atmosphere.

Proximate theopposite end of the cylinder 254, the inner `periphery thereof is provided with a piston stop 260 formed, conveniently, by an in wardly directed fiange or bead and the end of the bore 255 on the side opposite to the vent 251 is shown as closed by a removable plug 26| serving as an adjusting screw to place under desired tension the spring 262 urging the valve 259 in one direction. Proper adjustment of the spring tension renders the valve responsive only to predetermined degrees of sub-atmospheric pressure in the intake manifold .and results in correct or exact operation of the valve.

Opening into one side of the bore 255 is a port 263 to which the pipe 250 leading 'to the power cylinder 20 is connected. 'I'his port 263 is preferably elongated circumferentially of the bore in order that the passage through which the subatmospheric pressure is applied to the motor pistion 235 may have an adequate cross-sectional area substantially equivalent to` the cross-sectional area of the passage 250. f

The side of the bore 255 opposite to port 263 is shown as forn'ied with a by-pass passage 264 opening into a port 265 communicating with the tube 25|4 leading to the intake manifold I4 of the engine. By-pass'264 has two ports, one indicated at 266 leading to that bore portion within which the end of the piston 259 is exposed to the suction of the manifold, and the other port indicated at 261, opening into the bore upon the side opposite to the port 263.

The piston valve member comprises, in the illustrated embodiment, a cylindrical body portion 259 having a circular atmospheric pressure receiving flange 268 at the end nearest the vent 251 and a circular piston flange 26,9, which is subjected to the 'sub-atmospheric pressure of the intake manifold at the opposite end, and a cylindrical valve member flange 210 intermediate the two former flanges, which serves to control the communication between the motor port 263 and the source of sub-atmospheric pressure and the bleed port 21|, respectively, as conditions require.

, These three flanges 268, 269 and 21|) are all of the same diameter and closely t within the bore for reciprocation therein. They aregreater in diameter than the cylindrical body 259 so that the spaces between the body 259 and periphery of cylinder 254, defined by the respective flanges, form passages, one passage 212 establishing communication between the ports 261 and 263, and the rother passage establishing communication between port 263 and bleed port 21|.

The bleed port 21| is preferably .adjustable whereby air at exactly therequired rate of admission and volume may be admitted to the face 2410i the piston 235 of power cylinder 20 to permit the r'eengagement of the clutch easily and without shock. As shown, the bleed port 21| is rectangular in outline and is covered by a. disc 214 formed with a corresponding slot 215 and adjustably secured to the casing 254 by the pin and slot ,connection 216.

The piston valve 259 is normally urged to the position shown in Figure-25 by a spring 262 engaging the face of the piston ange 269, and seated on the spring tension adjusting screw plug 29|. The spring 262 is of such strength as to effectively position the valve to close oif the portv 263 from port 261 at sub-atmospheric pressures gines is effected by the plug 26|.

In order that the operation of the device may be clearly understood, it must be appreciated that when the engine is not operating, that is,' when it is at rest, the uid pressure of the gaseous contents ofthe intake manifold is substantially atmospheric pressure because the intake manifold is in communication with the inlet of the carburetor. When the crank shaft is turned over, as .by a self-starter, the fluid pressure in the manifold is sub-atmospheric and results from the down stroke of the piston. The sub-atmospheric pressure is increased somewhat, i. e., the suction is lessened, however, in the manifold by the .inrush of air through the inlet of the carburetor,

or, as is said, the vacuum is decreased. Thus,

. if a motor vehicle is standing and the engine is idling with the transmission gears out of mesh, the fluid pressure in the manifold may be found on a gauge to be, say, ten pounds (twenty inches of mercury). When the clutch is released, the propeller shaft connected through low gear with the engine, the clutch reengaged, and the throttle valve opened, there is a momentary increase in the fluid pressure, i. e., decrease in the vacuum, in the manifold, say, to three pounds. As the car gathers momentum, the Vacuum in the manifold increases until it registers ten pounds on the gauge again. This same'cycle of conditions occurs at every shift to another gear ratio. Again, when the vehicle is travelling along the level or on a down grade, it frequently happens that the momentum of the c ar, and hence the revolutions per minute of the propeller shaft, exceeds the speed of rotation of the crank shaft of the engine and hence, the engine being relieved of load, the vacuum in the manifold again increases It will thus be .seen that there is a condition of high vacuum in the intake manifold of the engine at times when there lis no load on the engine, and at such times there is no occasion for the engine to be clutched to the propeller shaft of the vehicle. At`other times, as' in starting and when there is a load on the engine, the propeller shaft must be clutched to the engine and this is at a period of low vacuum in the manifold.

In accordance with this invention, the controlling Valve for the servo motor is so constructed as to be actuated by the aforesaid predetermined high vacuum of the engine to open the communication between the pipes 250 and greater than a predetermined minimum, and its adjustment to suit particular conditions and en-v-v 25|, that is, between the power cylinder 20 and the intake manifold I4 of the engine.

YNormally, in periods of low vacuum in the manifold, thepiston valve assumes the position illustrated in Figure 25. It will be observed that the manifold port 261 and the power cylinder port 263 are disposed in transverse planes so spaced as'to permit .the valve flange 210 to lie therebetween and -cut off communication therebetween.

The valve piston port 266 is disposed on the other side of the stop 260 from the valve. In this position, with the valve closing off the motor 20 to 263 and a bleed port 21| are both uncovered and in communication so that atmospheric pressure 

